Familiar recharging methods include watching the voltage, current and temperature or impulse recharging and discharging methods or the regulation of the size of the recharging current. Thus in a certain manner maintaining or even improving the state of the capacity of the battery, or the speed it recharges, is resolved. These methods, however, can result in an increase of sediment in the battery after the fall-out of irreversible sulfatation as a result of the partial release of irreversible sulfatation from the walls of the electrodes which can even lead to a decrease in the life of the battery.
A number of inventions solve this problem.
The Czech Author's Certificate AO no. 250 340 solves the connection of a static source for the charging and discharging of a battery. The controlled charging and discharging of the battery is resolved by connecting a static source that contains protection, synchronization and anti-jamming, galvanic separation and voltage transfer, rectification, filtration, and contact reversal circuits, current sensors and a control unit circuit. The purpose of this connection is the possibility of the controlled charging and discharging of batteries, its disconnection by assessment of the end marks of charging or discharging, the possibility of influencing the charging characteristics with manual intervention and the contactless blocking of the source functions when incorrectly connected to the power supply or battery.
The Czech Author's Certificate AO no. 219 246 describes the connection for the recharging and pulse charging of batteries. The positive output terminal of the storage battery charger is connected to the inlet of the source of recharging impulses, whose outlet is connected to the positive input terminal of at least one storage battery.
The publicated Czech patent application no. PV 2001-1276 presents a method and connection for charging at least two connected cells and the batteries assembled from them with the charging proceeding in two consecutive phases. In the first phase the battery is charged by a constant current and this phase is ended at the moment the voltage of the batteries reaches a previously-chosen upper limit. During the course of the immediately-following second phase the flow of the charging current is interrupted for a period during which the voltage of the battery is decreased to a previously-chosen lower limit by internal discharging. Then the flow of the charging current of the battery is restored.
The publicated Czech patent application no. PV 3003-95 from a Swedish applicant describes the method and apparatus for charging lead batteries. Lead batteries are charged by repeatedly switching the unit for the recharging of the batteries on and off. For the charging of batteries the times of around one second for connecting and disconnecting is appropriate. In the case of maintaining the charge it is appropriate to charge the battery in pulses which are parts of the periods of supply voltage with intervals of about 10 seconds. The circuit is properly interrupted using a circuit breaker on the primary side of the transformer.
U.S. Pat. No. 6,100,667 establishes the minimization of the time of the charging cycle of the battery recharging system by maximizing the length of time for which this high constant charging current is applied to a dead battery. The control circuit can be controlled by a constant or variable internal reference voltage. If a variable internal reference voltage is used, the time of the charging cycle of the control circuit is further minimized by the compensatory technology of the charging current.
These aforementioned inventions document the current state of the technology in which various methods of charging and discharging lead and alkaline cells or batteries are utilized. The current worldwide state of recharging batteries is directed to the types of rechargers that control the charging current considering the internal resistance of the charged battery (a secondary source). With the gradual aging of a lead battery an irreversible sulfatation is created on its electrodes, which influences the value of the internal resistance of the charged battery leading to an error in the evaluation of the charging current when recharging. A battery recharged in this manner can then only attain values of partial charging which can result in its being damaged during operations if it is not secured against forbidden discharges.
Several additives solve another method of increasing the capacity of the cells or the batteries assembled from them, especially if lead or alkaline.
For example in Slovak patent no. 277 838 an additive in a powdered state which contains sodium peroxoborate, sodium pyrophosphate, glycides or their epimers is specified for lead batteries.
On the Czech market preparations under the brand names of AMPER PLUS, Supervit, Me{hacek over (c)}ta, and others are well-known for the regeneration of lead batteries filled with sulfuric acid electrolytes. Due to their relatively small effectiveness, these preparations did not prove successful on the market and did not remain.
Preparations based on the basis of peroxidic compounds created by an aqueous solution of hydrogen peroxide brought significant advancements in this area. Regenerative agents of this type are specified in Czech inventions, i.e. in Czech Author's Certificates nos. AO 262274, AO 271813, AO 271814, AO 271768, AO 278416.
Czech Author's Certificates nos. 260 591 and 272 401 describe the lead and alkaline battery regeneration method using these regeneration additives.
Czech Author's Certificate no. AO 260 591 describes the method of regeneration of mechanically undamaged lead and alkaline battery cells. The regeneration is carried out by adding an aqueous solution of hydrogen peroxide in batches to the aqueous solution of the electrolyte, though it is suitable for the cell to be partially charged before regeneration and recharged in the process of regeneration.
Czech Author's Certificate no. AO 272401 presents a method of regenerating secondary cells of lead and alkaline storage batteries. The electrolyte in the cells is replaced by a regeneration solution containing hydrogen peroxide in a concentration of from 0.01% to 2%. During the regeneration it is suitable for the cells to be partially charged or discharged with a current with a maximum value of 25% of the nominal value of the capacity of the cell in ampere-hours. After the regeneration the regeneration solution is replaced by a new electrolyte. For alkaline cells it is advisable to repeatedly change the regeneration solution while rinsing it with distilled water if necessary.
Using these methods of regeneration it is not only possible to renew the capacity of a used battery to its original state, but also resurrect a battery that was no longer capable of being used due to the highly oxidized surfaces of the electrode plates.
After the long-term usage and monitoring of the results of this type of regeneration a demand arose for perfecting the regeneration in the sense of an increase in the capacity of the regenerated battery to extend its life.
At the current time the life of lead batteries is extended with a filling of sulfuric acid by inhibiting the creation of passive surface layers on the plates of the battery's electrodes. Many various agents that are added either to the electrolyte or to the material of the electrode as an anti-agglomeration material are used to this effect.
In the Czechoslovak Author's Certificate no. 260 591 the method of regenerating mechanically sound lead and alkaline battery cells is described. The regeneration is carried out by adding hydrogen peroxide to the electrolyte while the total added amount of hydrogen peroxide is in the range of from 0.01% to 3% of the capacity of the electrolyte cell and a 30% to 40% aqueous solution of hydrogen peroxide is used.
The advantage of this solution is that it partially eliminates irreversible sulfation, yet if an adequate amount is not provided the preparation operates very actively and can damage the separators between the electrodes and thus destroy the battery.
The additive for lead and alkaline batteries is described in the Czech Author's Certificate no. 271 813. The additive is created by a combination of compounds from which one is saccharides and their derivatives dissolved in water and the others are peroxide compounds.
Compared to the preparations mentioned above, this preparation represents a considerable improvement, increased effectiveness and a slowdown in the process which is particularly advantageous for starting batteries.
A disadvantage is that it does not solve the removal of the hardened layers of irreversible sulfatation from the surface of the battery's electrodes.
In the Czech patent no. 278 416 an additive to lead batteries with a sulfuric acid electrolyte is described. The additive contains sodium peroxoborate in the amount of 50% to 70% of the mass, sodium pyro diphosphate in the amount of 15% to 48% of the mass, bisodium dinaphtylmethane disulfonic acid salt in the amount of 1% to 15% of the mass and glycides or their epimers in the amount of 1% to 20% of the mass.
This regenerative agent was tested but did not prove successful. The aforementioned bisodium dinaphthylmethane disulfonic acid salt cannot be stored in an aqueous solution with an ingredient of peroxide and other compounds without the stabilization of the solution. Therefore this salt was only used in powder form. Its disadvantage is the instability during storage because bisodium dinaphthylmethane disulfonic acid salt with sodium peroxoborate and sodium pyrophosphate can react all by themselves, even at temperatures of more that 30° C., which degrades the regenerative agent. They also react very quickly inside the lead cell as well as in an undesirable way, while it may damage the separators between the battery's electrodes by its fast reaction.
The disadvantage of the regenerative agent in accordance with Czech patent no. 278 416 is that the preparation in the given composition reacts long and slowly and this preparation only oozes to the surface of the electrode material, especially with batteries whose electrodes are protected by textiles.
In Czech patent 292 524, commonly owned herewith, a regenerative agent for lead batteries is described that contains 1 ml to 70 ml of sulfuric acid with a density of 1.01 to 1.35 g·cm−3, 0.1 g to 10 g of saccharides and/or aldehydes or their derivatives in solids, 0.1 g to 10 g of sodium and/or calcium bicarbonate and/or at least one hydroxide from the hydroxides of alkaline metals in solid for each liter of aqueous solution 1% to 40% of hydrogen peroxide. It can further include agent contents from 10.1 g to 10 g sodium peroxoborate and/or sodium tetra borate and/or sodium pyrophosphate. This regenerative agent represents a considerable improvement compared to the previous solution. Its advantage is the smooth regeneration of the battery's electrodes.
It was ascertained with the two-year monitoring of the application of this regenerative agent according to Czech patent 292 524 also that in some cases, such as the very solid surface of the electrode plates, its effect is slow.
CS AO No. 186 387 described an utilization of the mixture, with a contain of minimally of 90% dinaphthylmethane disulfonate and 0.1 to 99.9% of sulphuric acid and dinatrium sulphate in mixture of arbitrary ratio, with maximum of 5% technological impurities. This mixture is added to the active mass and/or the electrolyte of new lead battery. According to this invention, this mixture has 2-3 times greater dispersing effect than beech powder or Kortan QD, and allows faster discharging during low temperature and increasing of service life of starting lead battery during classic cycling. This invention concerns only a production of the new batteries namely of starting battery working on low temperature and a treatment of electrolyte in the new batteries.
The said mixture does not contain hydrogen peroxide and further oxidizing or reducing agents as the saccharides and/or aldehydes, bicarbonates and/or hydroxides of alkaline metals or peroxoborate, tetraborate, sodium pyrophosphate. This mixture is not suitable for regeneration of the used batteries or cells and for an increasing of its capacity.